Furnace



UNITED STA'll-IS rTENT OFFICE.

HORACE E. SMYTHE, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO THE S. R.

PITTSBURGH, PENNSYLVANIA, A CORPORATION 0F FURNACE.

Specification of Letters Patent.

Patented June 22, 1920.

Application led January 19x 1920. Serial No. 352,509.

To all `'wlw/1i `t may concern:

Be it known that I, Henson E. SMYTHE, a citizen of the United States, residing at Pittsburgh, in the county of Allegheny and AState of Pennsylvania, have invented new and useful Improvements in Furnaces, of which the following is a specification.

My invention relates to furnaces for heating ingots, slabs, billets, plates, or other nietallic material and for annealing or heat treating the same. It is applicable also to open-hearth melting, copper smelting and other types of metallurglcal furnaces.

The principal object of this invention is to assure proper combustion of the fuel constituents without regenerating the fuel gas. reversing valves, one for gas and the other for air. The air-reversing valve is shifted from time to time to cause the air for combustion to enter the furnace chamber alternately from opposite sides, and to cause the waste gases to pass therefrom through the reversing valve to the stack. The gas-reversing valve is also shifted to cause the gas to enter the furnace chamber alternately from opposite sides along with the air, but the waste gases do not pass through this valve, which has no connection with the stack. By this arrangement there can be no leaking of gas or fuel through the valve to the stack. No checkers are provided in the furnace for regenerating the gas, nor docs any waste gas pass from the furnace chamber through the gas passages, but all the waste gases pass through air regenerators which are connectedto the. stack by the air-reversing valve.

Referring to the accompanying drawings, which illustrate my invention in connection with a soaking-pit furnace for ingots, Figure 1 shows two furnaces separated by a di vision wall and employing a single stack flue, the lower half of the figure being a plan view of one furnace and the upper half a horizontal section of the other furnace. the section being taken on the line l-l on Fig. 2. Fig. 2 is a vertical section of Fig. 1 on either line II-II; Fig. 3, a vertical sec tion of Fig. 1 on the line II-IH and also on the line HIE-III, so far as it extends to the rear; and Fig. 4, a cross section on the line IV-IV on Fig. 1.

On the drawings, A and B designate two furnaces, having the same construction ex- Each' furnace is equipped with twoV cept in a few details to which attention will be directed hereinafter. The upper half of Fig. 1 shows the furnace A and the lower haif, the furnace B.

'The furnaces have the common vertical wali or partition 1 and the outer side walls and 3. The rear portions of the furnaces have a less height than the central and forward portions, as they contain merelv the stack fines, the reversing valves, and the flues for carrying the gas and air to the said central and forward portions, and the waste products away from the latter. The central and forward portions, or what may be called the main portions, of the furnaces have the front wall 4 and the rear wall 5, both reaching from the roofs 6 to the foundation. or Hoor i'.

The main portion of each furnace has a soaking-pit or furnace chamber 8 supported at some distance from the fioor 7 by arches 9 and by the shoulders 10 in the thick trans verse walls 11 and 12. Flues or combustion chambers 13 and 14 lie in each furnace hetween the roof 6 and the top of the respective transverse vertical walls or partitions 11 and 12 and preferably extend the entire width of each of these walls, that is` from the wall 1 to the outer wall of each furnace. The combustion chambers 13 and 14 in each furnace are connected to the pit S by the passages l5 und 1G, respectively, which are .were continuatious of the combustion chainbers. The combustion chambers 13 and 14. at their outer ends communicate by the rcspective horizontal passages or ports 17 and 18 with the upper ends of the air regenerators or chambers 19 and 20, respectively. The ports 17 and 18 are openings through thel vertical transverse walls or partitions 2l and 22. respectively, the latter being spaced' from the. vertical walls 11 and 12, rcspec tively. so as to form the narrow vertical non-regenerative gas-supply chambers 2B and 24, respectively. which communicate with the respective chambers 13 and 14 by means of thc ports 25 and 26, respectively. The outer ends of the air chambers 19 and 2O are closed by the walls 4 and 5.

Each furnace has a pair of super-posed gas-Hees 2i' and 28, the lower of which runs along the Hoor "iy and both of which lic in the furnace A along the wall 2, and in the furnace B along the wall 1. The Hue 28 runs in each furnace from the rear end to the front end. nhere it opens into the hottoln of the gas rhanlher 23. and the flue 2T runs for` \vardl v only lo the gas f'liaxnher 24. with the lower end of uhh-h it eonununirates. The rear ends o lx the llues 2T and 2H open into the upwardly extending tlues 2t) and 3l?. respectivel v. whieh eonnnnnieate with the opposite ends of the reversing-valve eharnher 31, provided rentrait) al-ove with the gas inlet 252. Between this inlet and the llues 2!) and Ilt) is the reversing valve i) whieh. when in the full'line position. permits gas to enter the flue 29 and prevents it from entering the flue 311i. and, when in the dotted position. permits gas to enter the flue 3U and prevents it entering the flue 29.

E-.uh furnace has also a pair of superposed air fines 31 and 35 parallel with the llues 2T and and in the furnace A lying next to the wall 1 and in the furnace B. next to the \va|l Il. laeh flue 35 extends entirely to the front of its respeetive furnaee andl opens into the hottom of the respeetive regenerative ehamher l!) while the flue Ill runs onl)Y to the hottoxn ofthe regenerative Chamher 2U. into whieh it opens. The rear ends of the lines IH and 215 open into the upwardly-extentling lines 3G and 8T which open into the opposite ends of the valve easing it. provided eentrally ahove with the air-inlet in). Between the inlet. 35| and the llnes :iti and 2V' in eaeh furnace is the reversA ing valve 413. whieh. when in the full-line position. permits air to enter the flue 36 and the waste gases in the flue 3T to enter the` Hue -11 direetltv heneath the valve. From the flue 11 in eaeh furnare the said waste gases traverse the rearwardly extending flue 4Q. whieh in earh. furnaee opens into the romnlon stark llne til. There is no flue. eonneetion between the reversing-valve easing 31 y and the thu-s 41. 12. or 43.

The operation of one of the furnaees is as follows: Vl`he reversing valves ll and 4'() heiug in their fullline positions, the gas passes from theinlet Si through the llues 29 and :3T into the gas ehamlver :4 and them-e through the ports 2G into the romlnustion ehaxnher 11. where it meets with regenerated air eoniing from the inlet lt) hy nav of the lines 3G and 3-1. the regenerator ehamher 2U, and the. ports 1S. The burning gas passes through the passage 1G into the soaking-pit, or furnace ehaniher 8, and thence to the staek tlue -13 hy way of the passage 15.y the ehamher 1?. the ports 1T, the regenerator ehamher 19. the lues 35 and 37. the reversing valve easing. and the fines 11 and 4Q. 1n this operation the air is ahsorhing heat from the previously heated regenerator"chamber .20 and the waste, products of eornhustion are heating the regenerator ehamher 19. 'hen the regenerator chamber 19 has het-ome prtnierlxv heated` the reversing valves are shifted to the dotted-line positions. the gas then passing from the inlet 232 through the Ilues 3U and 2H. the ehaniller 2. and the ports '25 to the romhustion ehanilaer l where it meets air whieh flows from the inlet Il through the lines 25T and 21T. the regenerator rhamher 1i).y and the ports 1T to the eoxnhustion ehamher 13. From the latter ther hln-ning gas passes through the passage l into the soaking-pit S. from uhieh the waste gases pass to the stark flue lil h v way of the passage 1G, the eharnher 1l, the ports 1H. the regeneliator rhamher 21|, the Haes` 2H. and 3G. the valve easing 23H. and the llues 41 and 42. ln this ease the regenerator ehaln her 2U is reheated while the air is ahsorhiin heat from the ehamher 19. The eolnplet operation just given is repeated as long a. the furnace is in operation.

It is to be noted that the Waste gases do not reach the stack h v Way of the gas-reversing valve. hut wholly through the airA reversing valve. There is.y there fore` no leakage of gas from the gas-reversing valve easing to the stark as would oeeur if the wasteI products should traverse the same. The heated air from the air regenerators 19 and :2li passes through ports in the walls di viding them from the gas chambers 23 and 21 and then passes direetlyY over the top of the gaseous fuel eoming from the ports 25 and 2G. therebyr effecting a` proper. eeonoim ieal. and improved romhustion. A\ll the` Waste gases pass through air regeneratorsl only. thereby preheating the air t0 a high temperature and assuring proper eolnhustion. i

In ease this invention is to use natural gas or fuel oil intrmlueed through pipes. the pipes would deliver the fuel alternately to the ports 25 and 26. while the air would pass as deserihed. Coke oven gas and blast furnace gas would he introduced in the same wav.

elaini:

1. In a furnaee structure. a furnace chamber, n1 lans for reversing the How of air and gas to the said ellaniher, a stark flue. and means preventing the waste gases from flou ing through the gas reversing means and through the gas passages hetween the chamher and the gas reversing means.

2. In a fumare strueture, a fui-nare ehaniher, a Combustion ehamher opening into eaeh side of the furnace ehamher. a gasreversing means, a passage leading from the said means to each eornhustion chamber. an air regenerator Connected to each romhustion ehalnber, an air-reversing means, a passage leading from the last named means to eaeh regenerator, and a staek flue eonneeted to the air-reversing means only.

Signed at Pittsburgh, Pa., this 10th day of January. 1020.

HR A CF. E. S UYTHIC. 

